1. Field of the Invention
The invention relates to a depalletizing system for a plurality of products stacked on pallets in layers according to the claims.
2. Description of Related Art
Especially major trade chains and discount stores face huge logistic expenditures for distributing the goods to their sales centers and sales outlets. Thereby the unmixed products are often temporarily stored in large amounts on so-called customer trays in corresponding high-bay storages in large distribution centers. These products are, however, delivered by the manufacturer to the distribution center unmixed and in layers on manufacturer pallets it is then required for the temporary storage to depalletize the unmixed pallets in layers.
This depalletizing of the unmixed products is significantly more difficult than the manufacturer's palletizing, since thus far large-scale manual depalletizing has been necessary due to the different forms, sizes, weights, and surface structures as well as the different outer packaging (trays, cartons, foils, papers, . . . ), and consequently great personnel expenditures ensue. The personnel's health is also strongly impaired by this manual depalletizing in the course of the shifts, whereby the law limits the maximum load to be lifted during a shift to 3000 kg/person.
In order to minimize these personnel expenditures, EP 1 890 054 B1 discloses a robot-assisted solution in which, for depalletizing, a removal unit laterally seizes a layer to be lifted of the products/trading units arranged on the pallet with two rollers in a frictionally-engaged way, and lifts the layer, and then runs in two support bases from these sides so that the lifted layer is supported. This layer is then put on the afore-mentioned customer tray and temporarily stored unmixedly in the high-bay storage.
It is a disadvantage of this known solution that some product layers are not stable enough for being laterally lifted in a frictionally-engaged way, since, for example, the products themselves or their outer packaging are deformed when the rollers are applied. In this case, the products have to be manually depalletized as was described in the beginning.
In U.S. Pat. No. 5,265,712, a similar system is described in which lifting is not carried out by rollers, but by a so-called ‘knife edge’ in which a belt wraps around a rolling arrangement and which has a deflection pulley with a small diameter on the front side. This front side laterally seizes—similar to the afore-described embodiment—the layer to be lifted so that it is lifted over the revolving belt, and the knife edge can run in under the layer to lift it.
Such an arrangement has the same disadvantages as the afore-described robot solution.